A new coherent optical detection technique employing coherent frequency-domain reflectometry and a novel optical frequency sensor is demonstrated for high-precision optical path-length measurements. Using pulsed laser sources, an improvement of more than two orders of magnitude in spatial resolution over conventional optical coherent frequency domain reflectometry techniques is demonstrated. Varyi...
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The wavelength-sensitive transparent properties of direct-bandgap semiconductor optical diodes (DBSODs) can be utilized for wavelength sensing. A simplified theory is used to describe the operation principles of such wavelength sensing schemes. The principles fan be applied to realize different measures, including sensing with or without pilot tone for single wavelength or multiple wavelengths. Th...
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The efficiency of transmission control of dispersion-managed solitons by means of in-line synchronous intensity modulation is numerically analyzed. We demonstrate that intensity modulation may lead to dramatic improvements in the transmission performance of 40-Gb/s dispersion-managed solitons. In particular, we identify the locations within the dispersion map where synchronous intensity modulation...
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A novel structure of the intrinsic Fabry-Perot interference (IFPI) fiber temperature sensor is presented. The sensor uses two different core diameter fibers and produces a reflective mirror by fusing uncoated bare fibers. This procedure not only solves the problem of controlling thickness and reflectance of the thin film but also provides easier and cheaper technologies for IFPI fiber sensors. The...
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The period and length of a fiber grating structure can be reconstructed from its corresponding complex reflection coefficient using time-frequency signal analysis based on Wigner-Ville and spectrogram distributions. We provide an experimental demonstration of this synthesis technique on two fiber grating structures and obtain good agreement between the reconstructed values and those expected based...
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The perfectly matched layer boundary condition for arbitrary anisotropic media is incorporated into the approximate scalar beam propagation method. The procedure is based on a finite-element method for three-dimensional anisotropic optical waveguides with off-diagonal elements in a permittivity tensor. In order to treat a wide-angle beam propagation, the Pade approximant operator is employed. To s...
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The two-dimensional (2-D) iterative finite difference beam-propagation method (IFD-BPM) is modified to model the cylindrically symmetric three-dimensional (quasi-3-D) second-order nonlinear wavelength conversion in quasi-phase-matched condition. The study shows that the difference between the 2-D and 3-D schemes is small for the guided waves but large for the nonguided beams. The comparison with e...
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The cascadability of semiconductor optical amplifier (SOA) gates by using holding light injection is numerically and experimentally investigated. Our experimental results show that the signal bit error rate after two cascaded SOA gates will be larger than 10-9 without holding light injection; however 11 SOA gates can be cascaded with holding light injection. The results show that the nu...
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This paper reports a novel launch scheme for coupling light into the skew rays of a graded index fiber. This is accomplished by utilizing a diffractive optical element in conjunction with a single mode fiber to mode match a graded index fiber. Results are used to confirm the fact that the element does improve the coupling into the skew rays of graded index fiber. This approach offers an alternativ...
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A theoretical and experimental investigation is reported on a novel all-fiber technique for interrogation of interferometric low-finesse Fabry-Perot cavities. It is based on the modulation of the spectral transfer function of a wavelength-division multiplexer. Results are given when both serrodyne and sinusoidal modulation formats are considered
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We investigate efficiency of four-wave mixing (FWM) generation in quasi-distributed erbium-doped fiber (EDF) sections under general power evolution conditions. Measured FWM efficiencies are found to be in a good agreement with newly developed formulae applicable to waveguides with spatially and spectrally varying gain. Inoue's work describing FWM process in multiple amplified spans is generalized....
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This paper proposes an architecture for routing Internet protocol (IP) packets directly on optical networks. The use of label switching is assumed in the IP routers, while a new routing architecture is introduced to transport IP packets across an optical backbone network. The architecture is based on a two-tier multiplexing approach with wavelength division multiplexing (WDM) addressing the number...
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This paper describes multiplexing schemes for interferometric fiber sensors based on time-division multiplexed and dense wavelength-division multiplexing using optical add/drop multiplexers. The results of an experimental arrangement, which is based on one of the architectures, is also presented. Topics include a discussion of the noise sources in the system, dynamic range, and a characterization ...
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A full vectorial three-dimensional beam-propagation method (BPM) based on the finite-element method is described for the analysis of second harmonic generation (SHG). Quasi-phase-matched SHG devices with periodically domain-inverted GaAlAs- and LiTaO3-based waveguides are analyzed. The influences of the shape of domain-inverted regions and of the inversion width on the conversion effici...
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A new efficient technique that models the behavior of pulsed optical beams in homogenous medium, metallic and dielectric waveguides, is introduced and verified using both linear nondispersive and dispersive examples that have analytical predictions. Excellent accuracy results have been observed. The method is called time-domain beam-propagation method (TD-BPM) because it is similar to the classica...
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This paper presents a new technology for constructing IP over photonic systems. An IP with multiprotocol label switching (MPLS) over wavelength division multiplexing (WDM)-based broad-band IP network architecture and protocol is proposed and analyzed in this paper, which supports variable-length IP-like optical packet label switching and optical virtual path routing. This system tries to merge int...
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New, compact multimode interference couplers with tunable power splitting ratios have been realized. Experiments show large tuning ranges. Such couplers are needed to optimize ON-OFF ratios in interferometric devices and may find applications as extremely compact switches
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A performance analysis of an optical clock extraction circuit based on a Fabry-Perot filter (FPF) is presented. Two analytical methods, time-domain and frequency-domain analysis, are developed in this paper. Time-domain analysis shows that there is no phase jitter in the extracted optical clock if the free spectral range (FSR) of the FPF is exactly equal to the signal clock frequency. Based on thi...
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Using numerically simulated results, it is shown that an efficient laser-to-fiber coupling is possible by incorporating a uniform spot-size converter (SSC) with two nonidentical but phase matched optical waveguides. Using a “diluted” waveguide with a low index contrast, the power coupling loss can be significantly reduced from 10.4 dB to only 1.15 dB and at the same time 1.0 dB alignme...
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We present a novel measurement setup that can be used for the complete characterization of fiber Bragg gratings and wavelength selective fiber-optic devices. Our setup is based on the phase-shift method (PSM), which we have modified to include the measurement of polarization-induced effects such as polarization-dependant loss (PDL) and polarization-mode dispersion (PMD). We measure the spectral re...
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The wavelength tunability and the polarization characteristics of twisted polarization beamsplitting fiber couplers are investigated experimentally and analyzed theoretically. The measured spectrum transmissions and polarization characteristics agree well with the theoretical results. The wavelength working as a polarization beamsplitter can be tuned in the 1.3-1.75 μm wavelength range without ...
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Analytical expression of signal bandwidth of general straight and tapered N×N multimode interference (MMI) couplers is presented. The signal bandwidth is characterized as a function of mode relative energy, mode propagation delay time, and mode pulse broadening in the multimode section of MMI coupler. The model is used to evaluate the signal bandwidth of specific couplers. Results indicate t...
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We present a technique for the shaping of short pulses based on the use of superstructured fiber Bragg gratings (SSFBGs). We apply this technique to demonstrate the generation of 20-ps rectangular pulses by phase and amplitude profiling of 2.5-ps soliton pulses. Numerical calculations validate our experimental findings
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Aims & Scope

The Journal of Lightwave Technology is comprised of original contributions, both regular papers and letters, covering work in all aspects of optical guided-wave science, technology, and engineering. Manuscripts are solicited which report original theoretical and/or experimental results which advance the technological base of guided-wave technology. Tutorial and review papers are by invitation only. Topics of interest include the following: fiber and cable technologies, active and passive guided-wave componentry (light sources, detectors, repeaters, switches, fiber sensors, etc.); integrated optics and optoelectronics; and systems, subsystems, new applications and unique field trials. System oriented manuscripts should be concerned with systems which perform a function not previously available, out-perform previously established systems, or represent enhancements in the state of the art in general.